JPH04295753A - Carbon monoxide gas detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon monoxide gas detector that allows readjustment to be easily performed in the event that the sensor output at the sensor 0 level changes after adjustment is completed.

0002

2. Description of the Related Art Modern combustors are equipped with carbon monoxide gas detectors to prevent incomplete combustion.

[0003] Such a carbon monoxide gas detector (hereinafter referred to as a gas detector) includes a carbon monoxide gas sensor (hereinafter referred to as a sensor) that detects carbon monoxide gas (hereinafter referred to as CO gas), and a sensor output. The CO gas is composed of a sensor output detection means for detecting CO gas and adjusting the relationship between concentration and output, and an alarm such as a buzzer that is activated when the CO gas reaches a certain concentration.

[0004] Since this sensor outputs a sensor output proportional to the gas concentration, the gas concentration is known from this sensor output. The alarm set point of the alarm is then set by the sensor output. Therefore, it is required that the relationship between this sensor output and concentration is always kept constant.

[0005] Therefore, for example, a few minutes after ignition of the combustor is set as a predetermined time point for adjustment, and the sensor output at this time is used as the sensor 0 level output (adjusted to 0, for example) as a reference point for all the above-mentioned steps. As shown above, the alarm set point of the alarm device is set.

[0006] If the sensor output at this sensor 0 level changes, the operating concentration will change since the alarm set point of the alarm is generally fixed. For example, as shown in Figure 6, even if the adjustment is made to operate at 5 mV and 1000 ppm, if the sensor output at the 0 level changes from a to b to c, the set concentration will eventually become 15 mV and 1000 ppm.
It will operate at concentrations of 00 ppm and 500 ppm.

Such a change in the sensor 0 level output often occurs, and for example, when this gas detector is installed in a combustor and shipped after 0 level adjustment, excessive damage during the transportation and installation process may occur. The sensor 0 level output may change (move to 0 point) due to shock, vibration, etc. In such a case, after installation, the factory standard sensor 0
The level output will be checked, and if it fluctuates, it will be reset, and the entire system will be readjusted based on this.

[0008] However, this adjustment is a troublesome work, and it is difficult for on-site workers to make the adjustment.

[0009] The sensor 0 level output before shipment as described above is sometimes referred to as the reference sensor 0 level output, and the sensor 0 level output at the time of inspection after installation is sometimes referred to as the sensor 0 level output at the time of inspection.

0010

[Problems to be Solved by the Invention] As mentioned above, conventional gas detectors have the disadvantage that when the sensor 0 level output changes, it is difficult for the user of the combustor to easily readjust it. there were.

The present invention has been made to solve the above-mentioned disadvantages, and an object of the present invention is to provide a gas detector that has a built-in adjustment means to facilitate readjustment of the reference sensor 0 level output.

0012

[Means for Solving the Problem] In order to achieve the above object, the invention according to claim 1 provides a sensor output detection means having a carbon monoxide gas sensor and detecting and outputting the sensor output of the sensor; A monoxide device comprising an alarm means having an alarm set point set based on a reference sensor 0 level output set for the sensor output from the output detection means, and an adjusting means for checking the reference sensor 0 level output. In the carbon gas detector, the adjustment means includes a sensor output storage circuit that stores the reference sensor 0 level output, and a sensor output storage circuit that stores the reference sensor 0 level output, and a sensor output storage circuit that stores the reference sensor 0 level output.
A comparison circuit that compares the level output and the sensor 0 level output at the time of inspection set at the time of inspection and outputs the difference, and a correction of the alarm set point or the The carbon monoxide gas detector is characterized in that it has a correction circuit that performs one of the corrections to make the sensor 0 level output at the time of inspection match the reference sensor 0 level output.

[0013] Furthermore, the invention according to claim 2 provides a sensor output detection means that has a carbon monoxide gas sensor and detects and outputs the sensor output of the sensor, and a sensor output from the sensor output detection means. A carbon monoxide gas detector comprising an adjustment means for checking a reference sensor 0 level output, the adjustment means being configured such that the sensor 0 level output at the time of inspection set at the time of inspection is set with respect to the reference sensor 0 level output. a determination circuit that determines whether or not it is within the specified tolerance range and displays the result; and a zero point adjustment circuit that corrects the sensor 0 level output at the time of inspection to within the tolerance range based on the display of the determination circuit. This is a carbon monoxide gas detector characterized by having the following features.

[0014]

[Operation] In the invention according to claim 1, there is provided a comparison circuit that compares the reference sensor 0 level output set in the initial adjustment and the inspection sensor 0 level output obtained at the time of inspection, and outputs the difference; Based on this output, adjustment means is provided to either modify the alarm set point of the alarm or to match the sensor 0 level output during inspection with the reference sensor 0 level output, so readjustment can be done easily and accurately. I can do it.

In the invention as claimed in claim 2, the determination circuit determines whether or not the sensor 0 level output during inspection of the gas detector is within the allowable range of the reference sensor 0 level output, and if not, the adjustment means is operated. This allows easy and accurate readjustment.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be explained below with reference to a first embodiment and a second embodiment shown in the drawings.

First, a first embodiment will be explained with reference to FIGS. 1 to 3. The gas detector of this embodiment is comprised of a sensor output detection means 1, an alarm means 2, and an adjustment means 3, and the adjustment is a reset method.

The sensor output detection means 1 is a catalytic combustion CO
It consists of a sensor 11 that detects CO gas, and a sensor output detection circuit 12 that drives the sensor and extracts the sensor output.

The alarm means 2 consists of an alarm device 21 equipped with a buzzer, and the alarm set point is set based on the 0 level output of the reference sensor.

The adjustment means 3 has a comparison circuit 31, which is connected to the sensor output detection circuit 12, and which compares the reference sensor 0 level output with the sensor 0 level output at the time of inspection (at the time of reset).
Compare the level output and output the difference. Further, a sensor output storage circuit 32 is connected to this, and the reference sensor 0 level output, the sensor 0 level output at the time of inspection at the time of reset, etc. are stored in this.

Further, an alarm set point calculation circuit 33 is connected to the comparison circuit 31, and this calculates an alarm set point based on the difference outputted from the comparison circuit 31. Furthermore, it is connected to this circuit and to the comparison circuit 31 to store the calculation result from the alarm set point calculation circuit 33,
An alarm set point storage circuit 34 is provided which sends this to the comparison circuit 31 and the alarm 21.

Furthermore, a reset button 35 is connected to the comparison circuit 31, and is used to command the comparison circuit 31 to operate and reset it at the predetermined time point mentioned above, and is connected to the sensor output detection circuit 12. The timer circuit 36 provided here is for performing this with a timer. Note that the alarm set point calculation circuit 33 and the alarm set point storage circuit 34 constitute a correction circuit 37.

Each part of this embodiment is constructed as described above, and the overall operation will be explained with reference to the flowchart of FIG. 2.

[0024] In step P1, a combustor is installed.

[0025] In step P2, this is ignited.

[0026] In step P3, do you press the reset button 35? If YES, a reset command is issued at a predetermined time in step P4, and the sensor output is thereby read from the sensor output detection circuit 12.

At step P5, the reference sensor 0 level output is read from the sensor output storage circuit 32.

At step P6, the sensor 0 level output at the time of reset (during inspection) and the reference sensor 0 level output are compared, and the difference is input to the alarm set point calculation circuit 33 to calculate the set point. This revised set point is input to the alarm 21 via the alarm setting storage circuit 34.

In step P7, the sensor 0 level output at the time of reset (during inspection) is stored in the sensor output storage circuit 32 in preparation for the next adjustment.

The alarm set point corrected in step P8 is stored in the alarm set point storage circuit 34.

At step P9, a normal monitoring state is entered.

[0032] If NO (do not press the reset button) is selected in step P3, a normal monitoring state is entered in step P9.

As shown in FIG. 3, the relationship between the reference sensor 0 level output d and the sensor 0 level output e at the time of reset (at the time of inspection) in the above-described embodiment is such that the sensor 0 level output at a predetermined time (several minutes after ignition) Regarding the sensor output at the sensor 0 level at the time of setting), the reference sensor output d is 0, and the reset sensor output e is higher by 2 mV. Therefore, in order to keep the margin between the sensor output e at reset and the alarm set point m the same as at the time of adjustment, the revised alarm set point n is set to 2.
mV is set high.

Although the alarm set point is modified in this embodiment, the same result can be obtained even if the sensor output at the time of reset (during inspection) is modified.

Furthermore, since an arithmetic circuit is provided, correction can be completed quickly and accurately.

Next, a second embodiment will be explained with reference to FIGS. 4 and 5. This sets the sensor 0 level output to L during inspection.
This is a manual correction method based on the ED display.

The present embodiment is composed of a sensor output detection means 5, an adjustment means 6, and an alarm means (not shown). Since the alarm means is not adjusted, its explanation will be omitted.

The sensor output detecting means 5 is the same as that in the above embodiment, so a description thereof will be omitted and the same reference numerals will be given.

The adjusting means 6 has a determination circuit 61 in which an upper limit value and a lower limit value are set, and outputs an upper limit output when the input is above the upper limit value, and outputs a lower limit output when the input is below the lower limit value. are doing. Further, this determination circuit 61 is connected to an upper indicator 62 that is activated by these outputs, an LED 63 that is lit thereby, a lower indicator 64, and an LED 65. Furthermore, a zero point adjustment circuit 6 is connected to the sensor output detection circuit 12 and adjusts the sensor zero level output.
6 is provided.

When the reference sensor 0 level output is 0, the upper and lower limits are set to, for example, ±300 ppm.

Next, the overall operation will be explained with reference to the flowchart shown in FIG.

[0042] In step P1, a combustor is installed.

[0043] In step P2, ignition is performed.

In step P3, the sensor output is read from the sensor output detection circuit 12 at a predetermined time after ignition,
This is input to the determination circuit 61 as the sensor 0 level output during inspection.

In step P4, if it is determined that the sensor 0 level output is, for example, more than +300 ppm, that is, if it is NG, the LED 63 is turned on in step P5. Therefore, in step P6, the volume of the zero point adjustment circuit 66 is adjusted, and in step P7, the LED is turned off.

At step P8, a normal monitoring state is entered.

[0047] If it is OK in step P4, the normal monitoring state is entered as it is.

This concludes the explanation of this embodiment.

Furthermore, as in this embodiment, correcting the sensor output during direct inspection does not affect the alarm means.
The device is simple. Also, the fact that the direction of adjustment and completion can be confirmed on the display is extremely convenient. Further, in the above embodiment, the LED display and output determination circuit are built into the detector circuit, but this circuit section can be separated from the detector circuit and the same effect can be obtained as an inspection checker.

Next, a case will be described in which a combustor is inspected in a non-combustion state using the gas detector of each of the above embodiments.

[0051] When inspecting a new appliance, the sensor power is turned on without gas being supplied, and the 0 level output is adjusted in the same manner as in the first and second embodiments. In this case, the zero point deviation width during combustion and non-combustion is determined in advance as a correction, and estimated setting is performed.

As an example, when a catalytic combustion type CO sensor is installed on the exhaust side of a No. 16 water heater, the difference between the level during non-combustion and the level during combustion is approximately 3 mV, so it is set to +3 mV during adjustment. Then, during actual combustion, 0
It is possible to make it mV.

[0053]

[Effects of the Invention] As detailed above, the carbon monoxide gas detector of the present invention has a built-in adjustment means, so even if the sensor 0 level output changes after adjustment, it can be adjusted at any time. Can be readjusted easily. Therefore, it has high performance and extremely high reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention.

[
Figure 2: Flowchart also explaining the action

[Figure 3] Output diagram showing changes in sensor output as well

FIG. 4 is a block diagram showing the configuration of a second embodiment of the present invention.

[Figure 5] Flowchart also explaining the action

[Fig. 6] Diagram explaining the conventional example

[Explanation of symbols]

1 Sensor output detection means 2 Alarm means 3 Adjustment means 5 Sensor output detection means 6 Adjustment means 11 Carbon monoxide gas sensor (sensor) 31 Comparison circuit 32 Sensor output storage circuit 37 Correction circuit 61 Judgment circuit 66 Zero point adjustment circuit

Claims (2)

[Claims] Claim 1: A sensor output detection means having a carbon monoxide gas sensor and detecting and outputting the sensor output thereof, and a reference sensor 0 level output set for the sensor output from the sensor output detection means as a reference. A carbon monoxide gas detector comprising an alarm means having an alarm set point set by the reference sensor, and an adjusting means for checking the zero level output of the reference sensor, the adjusting means having an alarm set point set by the zero level output of the reference sensor. A sensor output storage circuit for storing information, a comparison circuit that compares the reference sensor 0 level output inputted from the sensor output storage circuit and an inspection sensor 0 level output set at the time of inspection, and outputs the difference, and this comparison circuit. and a correction circuit that either corrects the alarm set point or corrects the sensor 0 level output at the time of inspection to match the reference sensor 0 level output based on the difference between the 0 level outputs of both sensors output from the sensor. Characteristic carbon monoxide gas detector. 2. A sensor output detection means having a carbon monoxide gas sensor and detecting and outputting the sensor output thereof, and checking a reference sensor 0 level output set for the sensor output from the sensor output detection means. A carbon monoxide gas detector configured with an adjusting means, wherein the adjusting means determines whether the sensor 0 level output at the time of inspection, which is set at the time of inspection, is within a tolerance range set with respect to the reference sensor 0 level output. A device characterized in that it has a determination circuit that determines whether or not the product is present and displays the result, and a zero point adjustment circuit that corrects the zero level output of the sensor at the time of inspection to within the allowable range based on the display of the determination circuit. Carbon oxide gas detector.